Nitrides such as gallium nitride (GaN), aluminum nitride (AlN), and aluminum gallium nitride (AlGaN) have a high dielectric breakdown electric field and a high carrier velocity, and hence application to a high-output and high-frequency electronic device or optical device is expected. However, there is a problem in that output characteristics are limited due to self-heat generation at die time of a high output operation.
As a countermeasure therefor, for example. Patent Document 1 discloses a semiconductor device including a diamond layer embedded in a hole provided in a bottom surface of a substrate, a single-crystal nitride layer provided on an upper surface side of the substrate, and a device layer provided thereon. Diamond has the highest thermal conductivity among substances and is excellent in heat dissipation performance, and hence a field effect transistor including diamond can alleviate the limitation on output characteristics, enabling a high output operation.